Problem - Kevin Tafuro

#include
#include
/* This value needs to be the output size of your pseudo-random function (PRF)! */
#define PRF_OUT_LEN 20
/* This is an implementation of the PKCS#5 PBKDF2 PRF using HMAC-SHA1. It
* always gives 20-byte outputs.
*/
static HCRYPTHASH InitHMAC(HCRYPTPROV hProvider, HCRYPTKEY hKey, ALG_ID Algid) {
HMAC_INFO HMACInfo;
HCRYPTHASH hHash;
HMACInfo.HashAlgid = Algid;
HMACInfo.pbInnerString = HMACInfo.pbOuterString = 0;
HMACInfo.cbInnerString = HMACInfo.cbOuterString = 0;
if (!CryptCreateHash(hProvider, CALG_HMAC, hKey, 0, &hHash)) return 0;
CryptSetHashParam(hHash, HP_HMAC_INFO, (BYTE *)&HMACInfo, 0);
return hHash;
}
static void FinalHMAC(HCRYPTHASH hHash, BYTE *pbOut, DWORD *cbOut) {
*cbOut = PRF_OUT_LEN;
CryptGetHashParam(hHash, HP_HASHVAL, pbOut, cbOut, 0);
CryptDestroyHash(hHash);
}
static DWORD SwapInt32(DWORD dwInt32) {
__asm mov eax, dwInt32
__asm bswap eax
}
static BOOL PKCS5InitialPRF(HCRYPTPROV hProvider, HCRYPTKEY hKey,
BYTE *pbSalt, DWORD cbSalt, DWORD dwCounter,
BYTE *pbOut, DWORD *cbOut) {
HCRYPTHASH hHash;
if (!(hHash = InitHMAC(hProvider, hKey, CALG_SHA1))) return FALSE;
CryptHashData(hHash, pbSalt, cbSalt, 0);
dwCounter = SwapInt32(dwCounter);
CryptHashData(hHash, (BYTE *)&dwCounter, sizeof(dwCounter), 0);
FinalHMAC(hHash, pbOut, cbOut);
return TRUE;
}
static BOOL PKCS5UpdatePRF(HCRYPTPROV hProvider, HCRYPTKEY hKey,
BYTE *pbSalt, DWORD cbSalt,
BYTE *pbOut, DWORD *cbOut) {
HCRYPTHASH hHash;
if (!(hHash = InitHMAC(hProvider, hKey, CALG_SHA1))) return FALSE;
CryptHashData(hHash, pbSalt, cbSalt, 0);
FinalHMAC(hHash, pbOut, cbOut);
Deriving Symmetric Keys from a Password | 139
This is the Title of the Book, eMatter Edition
Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.